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Biomedical subjects

D B Silk

Publications and source records attributed to D B Silk.

At least 19 recordsLinked to original sources
PubMed1992

Medical management of severe inflammatory disease of the rectum: nutritional aspects.

It is clear that the nutritional state of patients with inflammatory bowel disease is often impaired and can be improved by the provision of nutritional support. Improvement in nutritional status can be achieved as effectively with enteral as with parenteral nutrition. Nutritional support appears to have no primary therapeutic effect in patients with ulcerative colitis. With regard to nutritional support in Crohn's disease, parenteral nutrition should be restricted to use as supportive rather than primary therapy. Available information now seems to suggest that most of the benefits of parenteral nutrition in Crohn's disease are related to an improvement in nutritional state rather than as primary therapy, and its use should be restricted to the treatment of specific complications of Crohn's disease, such as intestinal obstruction related to stricture formation or short bowel syndrome following repeated resection. Although some doubt exists over the efficacy of oligopeptide-containing elemental and polymeric enteral diets, the present evidence indicates that chemically defined free amino acid-containing elemental diets have primary therapeutic efficacy in the management of acute exacerbations of Crohn's disease. As such, these diets are worthy of therapeutic trial in patients with severe Crohn's disease involving the distal colon and rectum, particularly in those patients who are malnourished and who prove to be resistant to treatment with a combination of topical corticosteroids and 5-aminosalicylic acid-containing compounds. Clinicians should be aware, though, that the beneficial effects are likely to be restricted to the short term, with high relapse rates by 1 year, this being particularly so in patients with distal Crohn's proctocolitis (Teahon et al, 1988). Volatile fatty acid enemas clearly have potential in the management of patients with severe steroid-resistant proctitis. Finally, one of the most important observations made in recent years is the one concerning the large losses of nitrogen that will occur in patients with inflammatory bowel disease treated with corticosteroids in the absence of adequate protein intake (O'Keefe et al, 1989). Hopefully the days of treating patients with severe inflammatory bowel disease with high dose corticosteroids and a peripheral dextrose or dextrose-saline drip have passed into history.

Colitis, Ulcerative↗
PubMed1992

Topical nonsteroidal anti-inflammatory gel for the prevention of peripheral vein thrombophlebitis. A double-blind, randomised, placebo-controlled trial in normal subjects.

A double-blind, randomised, placebo-controlled study was undertaken to determine whether topical application of a nonsteroidal anti-inflammatory gel to skin overlying peripheral vein cannula sites has a role in reducing the incidence or delaying the onset of peripheral vein thrombophlebitis. Fifty normal subjects had intravenous cannulae placed in right and left arms. Subjects were randomised to receive twice daily application of either active nonsteroidal anti-inflammatory gel or placebo gel to each cannula site. Cannula sites were observed and signs and symptoms of inflammation recorded up to 108 h. If any site had signs extending beyond 2 cm then the cannula was removed. Cannula sites that had 'active' gel applied had half the incidence of marked signs at 108 h (44% vs 22%, p less than 0.05). These results suggest that local application of topical nonsteroidal anti-inflammatory gel to cannula sites may have a significant role to play in the prevention of peripheral vein thrombophlebitis.

Administration, Topical↗
PubMed1992

Glycine nitrogen in total parenteral nutrition: two prospective clinical trials comparing the efficacy of high and low glycine containing amino acid solutions.

Glycine has been regarded as a poor source of nitrogen for total parenteral nutrition. Two prospective randomised cross over controlled clinical trials were undertaken to compare the efficacy of high and low glycine containing amino acid solutions in parenterally fed malnourished hypoalbuminaemic patients with gastrointestinal disease. In the first study (n = 9), amino acid solutions in which glycine accounted for 23% and 4% of total nitrogen were compared. No statistically significant difference was found in urea nitrogen/total urinary nitrogen excretion (mean (SEM) 83.4 (1.4) v 81.6 (1.7)%, p = 0.31), nitrogen balance (-1.9 (2.4) v -0.6 (2.0) g/day, p = 0.31) or plasma protein concentrations and blood urea nitrogen. In the second extended study (n = 5), there was no significant difference in net whole body protein synthesis (+1.3 (4.7) v-0.2 (3.7) mg/kg/hour, p = 0.69) or fractional (0.403 (0.070) v 0.480 (0.41)%/hour, p = 0.68) and absolute albumin synthesis rates (6.0 (0.9) v 7.2 (0.06) mg/kg/hour, p = 0.22), on comparing solutions of 25% and 8% glycine nitrogen. In addition, a significantly higher proportion of total urinary nitrogen comprised urea when patients received the low glycine containing amino acid source (81.4 (2.5) v 83.8 (3.2)%, p = 0.04). It is concluded that there are no apparent short term nutritional or metabolic disadvantages to using amino acid solutions that contain up to 25% of nitrogen as glycine in total parenteral nutrition.

Adult↗
PubMed1992

Do patients with moderately impaired gastrointestinal function requiring enteral nutrition need a predigested nitrogen source? A prospective crossover controlled clinical trial.

This prospective double blind randomised seven day crossover controlled clinical trial was carried out to determine whether enterally fed patients with moderately impaired gastrointestinal function require a predigested nitrogen (N) source compared with whole protein. Twelve malnourished patients with varying gastrointestinal abnormalities, who required enteral feeding, received 2.25 l of one of two isocaloric isonitrogenous enteral diets (1 kcal/ml, 4.8 g nitrogen/l) containing either predominantly medium chain peptides (tetra or higher peptides) or whole protein as the nitrogen source. Nitrogen absorption and balance were calculated from dietary intake and analysis of 24 hour total urinary and faecal nitrogen for the last five days of each study period. There was no significant difference in either stool weight (110 (SEM) (49) v 111 (32) g/d), nitrogen absorption (91 (2) v 89 (2)%) or nitrogen balance (+1.0 (1.3) v +0.6 (1.4) g nitrogen/d) between the peptide and whole protein nitrogen sources when all patients are considered. There was, however, evidence to suggest a nutritional advantage from administering an enteral diet whose nitrogen source comprises oligopeptides, rather than whole protein, to a subgroup of patients with small bowel disease.

Dietary Proteins↗
PubMed1992

Esophagogastrectomy: a consecutive single-center series.

We present a 7-year consecutive, nonselected, single-center series of patients (n = 140) submitted to surgery for esophageal or upper gastric malignancy. Follow-up data are complete for 96.4% of patients. Of 114 intrathoracic anastomoses, 74 (65%) were esophagogastric and 40 (35%) were esophagojejunal. Unresectable lesions were present in 26 (19%) patients. Age (mean +/- sd 64.6 +/- 11.1 years), and sex distribution were similar in all groups, while 36% of patients were over 70 years. There was no significant difference in the time from the onset of symptoms to presentation between the groups (p < 0.05). The values of admission hemoglobin, serum albumin, PaO2 or peak expiratory flow rate did not correlate with survival. There was no significant difference in 30-day operative mortality between the three procedures - esophagectomy 5%, thoraco-abdominal gastrectomy 10.8% and unresectable 11.5% (p > 0.05). The incidence of respiratory complications was the same whether a right (30%) or left (35%) thoracotomy was performed. Some 33% of patients were discharged from hospital after 14 days and 72% after 21 days (12.9% died in hospital). One-year survival was 33.4% for esophagectomy, 37.5% for total gastrectomy and 6% for unresectable lesions. The esophagectomy versus total gastrectomy survival curves were not significantly different, but there was a significant survival advantage when patients undergoing esophagectomy were compared with those who had unresectable tumors (0.02 > p > 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Early experience with the Bower percutaneous endoscopic gastrostomy tube.

Percutaneous endoscopic insertion of gastrostomy tubes is a technique becoming more widely used in the UK. It allows insertion of a gastrostomy tube without laparotomy, under local anaesthesia and sedation, and so operative insertion may eventually become a rarity. We report on our successful early experience with a new gastrostomy tube (Bower PEG) which does not require endoscopy if eventual removal is required, and describe the methods of insertion and removal.

Adolescent↗
PubMed1991

Effects of olsalazine and sulphasalazine on jejunal and ileal water and electrolyte absorption in normal human subjects.

The effect of sulphasalazine and olsalazine on jejunal and ileal water and electrolyte absorption was investigated in normal subjects by a steady state intestinal perfusion of a physiological glucose bicarbonate electrolyte solution in the absence and presence of increasing concentrations of each drug. (Olsalazine 0.25 g/l, 1.0 g/l, jejunum; 0.5 g/l, 1.0 g/l, ileum; sulphasalazine 0.25 g/l, 0.5 g/l, 2.0 g/l jejunum; 1.0 g/l, 2.0 g/l, ileum.) In the jejunum olsalazine at 1.0 g/l significantly inhibited water, sodium, chloride, and potassium absorption (p less than 0.05). In the ileum olsalazine at 0.5 and 1 g/l significantly inhibited glucose uptake (p less than 0.04) and water absorption (p less than 0.03). In the jejunum sulphasalazine had a dose related and significant inhibitory effect on water, bicarbonate, and sodium absorption and at 2.0 g/l an inhibitory effect on chloride, potassium (p less than 0.005), and glucose (p less than 0.05) absorption. In the ileum sulphasalazine had no significant effect on water and electrolyte absorption. All inhibitory effects were rapidly reversible. These data show that unexplained diarrhoea in patients with ulcerative colitis treated with olsalazine may occur as a consequence of inhibition of water and electrolyte absorption in the small intestine and that the mechanisms of inhibition of sulphasalazine and olsalazine are different.

Adult↗
PubMed1991

Hepatobiliary dysfunction associated with total parenteral nutrition.

We have reviewed and discussed data concerning the development of hepatobiliary dysfunction in the patient requiring TPN. The data above can be summarised in a short statement--TPN-related hepatobiliary dysfunction is multifactorial. Despite all the factors discussed, the patients underlying disease state and the severity of the illness may be the most significant factor in the development of hepatobiliary dysfunction. With our current state of knowledge it is only possible for the clinician to be aware which of his patients are most likely to develop problems, and to forecast the type of dysfunction that is most likely to occur. There is no treatment--apart from stopping TPN--but there are certain methods by which the incidence and degree of dysfunction may be minimised, or some of the complications (e.g. gallstones) treated. Fortunately in most cases the degree of dysfunction is both self-limiting and reversible on cessation of TPN.

Adult↗
PubMed1991

Development of thrombophlebitis in peripheral veins with Vialon and PTFE-Teflon cannulas: a double-blind, randomised, controlled trial.

A series of 54 normal subjects were randomised to have either a Vialon or a PTFE-Teflon peripheral vein cannula inserted in a vein in each forearm to observe the development of thrombophlebitis. Cannulas were inspected twice daily for up to 5 days to observe the development of three signs, erythema, oedema or hardness and one symptom, pain. Each sign and symptom was recorded twice daily at three points, the cannula insertion site, the mid-point of the cannula and the cannula tip. The degree of change was recorded as less than 1, 1-2 and greater than 2 cm. Any cannula causing any sign greater than 2 cm was removed. By the end of the study over 40% of both types of cannula had been removed. There were no significant differences between the numbers of each type of cannula removed at any time point throughout the duration of the study. There were no significant differences in the amounts of erythema or hardness, but minimally increased swelling was observed at the mid-point of the PTFE-Teflon cannulas (P = 0.022). Despite the theoretical superiority of Vialon as a cannula material, under controlled conditions there appears to be little difference in its inherent capacity to cause the thrombophlebitis.

Adult↗
PubMed1979

Adsorption of human serum albumin to Amberlite XAD-7 resin.

In the present study the conditions leading to tight binding of human serum albumin to the Amberlite XAD-7 resin without the use of chemical coupling agents have been defined. Optimal binding (10.97 mm/kg dry XAD-7) was achieved at pH 5.0 and adsorption conformed to a Langmuir isotherm. Theoretical analysis of the data suggest adsorption of a monolayer of albumin which is supported by the absence of visual surface coating on scanning electron micrographs. Binding of human serum albumin was reduced when two chemical coupling agents, glutaraldehyde and carbodiimide were included in the human serum albumin solution, the elution of adsorbed HSA from the resins under severe flow conditions was reduced, and the amount eluted was minimal in all instances.

Acrylic Resins↗
PubMed1979

Albumin-coated Amberlite XAD-7 resin for hemoperfusion in acute liver failure. Part I: adsorption studies.

Platelets adhere to most foreign surfaces. As a result, polymers and albumin have been suggested as possible coatings to improve the blood compatibility of such surfaces. Amberlite XAD-7 has a high affinity for human serum albumin (HSA) and several protein-bound toxic metabolites. In the present study it is shown that HSA can be tightly bound to Amberlite XAD-7 without the use of chemical coupling agents. Optimal binding was achieved at pH 5.0 and the adsorption conforms to Langmuir's isotherm. Theoretical analysis of data and absence of a residual surface coating visible with scanning electron microscopy suggest a monolayer of albumin. The amount of HSA eluted from the resin under severe flow conditions was negligible (approximately 1%). Furthermore, in stirred batch studies with human plasma, the HSA coating did not decrease the adsorptive capacity of XAD-7 for bile acids and bilirubin.

Acrylic Resins↗
PubMed1979

Albumin-coated Amberlite XAD-7 resin for hemoperfusion in acute liver failure. Part II: in vivo evaluation.

Albumin-coated Amberlite XAD-7 has been previously shown to be blood compatible in in vitro hemoperfusion experiments whith human blood. In this study, the preliminary results are reported on single hemoperfusions with albumin-coated XAD-7 resin in four patients with acute liver failure. The mean platelet count was 116+/-SE 16.3% of the initial arterial value and the mean white cell count was 96+/-SE 6.5% of initial at the end of four hours of hemoperfusion. Removal of bilirubin, phenols and substances in the middle molecular weight range by the resin was demonstrated. These preliminary results suggest albumin-coated Amberlite XAD-7 resin to be blood compatible and capable of removing protein-bound and middle molecular weight substances from patients with acute liver failure. Further clinical evaluation of repeated resin hemoperfusion is required to determine whether this treatment will be beneficial to patient survival.

Acrylic Resins↗
PubMed1979

Comparison of oral feeding of peptide and amino acid meals to normal human subjects.

Intestinal perfusion studies performed in man have suggested that amino acid nitrogen may be absorbed more rapidly from peptides than free amino acids. The aim of the present study was to compare the effects of the oral administration of peptides and free amino acids. Two isonitrogenous liquid test meals, one containing 50 g of a partial enzymic hydrolysate of fish protein in which approximately 80% of the nitrogen content was present as small peptides (peptide meal), and the other a mixture of free amino acids (amino acid meal) the composition and molar pattern of which simulated that of the peptide meal, were administered on separate occasions to six normal subjects intubated with a triple lumen tube. Both meals contained the reference marker polyethylene glycol. Fractional absorption of amino acid residues one and two hours after ingestion of the two meals was similar at three intestinal locations situated 120, 160, and 200 cm from the mouth of each subject, and at two hours 73.8% and 72.0% of the amino acid residues had been absorbed respectively by the time the contents of the peptide and amino acid meals reached the middle sampling port of the tube. The total sum of individual amino acid increments in plasma was significantly greater 30 minutes (p < 0.025) and one hour (p < 0.05) after ingestion of the peptide than amino acid meals. By three hours the total area under the two plasma curves was similar. Normal human subjects thus appeared to be capable of assimilating orally administered mixtures of peptides and free amino acids with equal efficiency. Secretion of fluid into the lumen of the upper small intestine, assessed by reference to dilution of the polyethylene glycol, was less after ingestion of the peptide meal. In clinical situations characterised by fluid and electrolyte malabsorption consideration might be given to using small peptides rather than free amino acids as the nitrogen source in nutritional diets.

Adult↗
PubMed1979

The use of prostacyclin, PGI2, in the prevention of platelet aggregation during charcoal haemoperfusion.

In previous studies severe side effects, including irreversible hypotension, platelet losses and rises in Swank screen filtration pressure, have been recorded during the treatment by charcoal haemoperfusion of patients with fulminant hepatic failure. It has also been demonstrated that rises in Swank screen filtration pressure in an in vitro test circuit are due to the presence of platelet aggregates. In this study Prostacyclin was infused at a constant rate, to give a blood concentration of 5 ng/ml, into the in vitro circuit just prior to the charcoal column. Rises in Swank screen filtration pressure were prevented, and it was also shown that the giving of a bolus dose of Prostacyclin (400 ng/ml blood concentration) reversed rises in Swank screen filtration pressure that have already occurred. On the basis of these findings, Prostacyclin would be expected to be of considerable clinical value in the prevention of adverse platelet reactions to charcoal haemoperfusion when carried out in patients with fulminant hepatic failure.

Adenosine Diphosphate↗